Around here, along the CA/MX border, lightweight 28-ga guns with 3/4-inch loads are becoming popular. For opening day, standard #9 skeet loads work well. For later in the season, after the birds have smartened-up, you might wanna go with #8s.
It's been my experience that you'll get better 7/8-oz performance from a 20-ga gun than from a downloaded 12-ga. If you wanna hump a big gun for nostalgia, don't worry about a 12-ga with 7/8-oz being overkill.
…12ga with the 1 1/4 oz loads.
Yikes, are those duck sized dove?